Compressible motor, implantation arrangement, and method for positioning the motor

ABSTRACT

The invention relates to a motor with a stator and a rotor, which can be driven about an axial direction. The invention is characterized in that at least one of the stator and the rotor, in particular the stator, which has a winding arrangement that can be supplied with a current, can be radially compressed and expanded.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/436,000, filed Jun. 10, 2019, now allowed, which is acontinuation of U.S. patent application Ser. No. 15/662,884, filed Jul.28, 2017, now U.S. Pat. No. 10,342,904, which is a continuation of U.S.patent application Ser. No. 15/028,588, filed Apr. 11, 2016, now U.S.Pat. No. 9,750,860, which is a national phase entry under 35 U.S.C. §371 of International Application No. PCT/EP2014/071705, filed Oct. 9,2014, published as International Publication No. WO 2015/052303 A1,which claims priority to European Patent Application No. 13188380.3,filed Oct. 11, 2013, the disclosures of which are hereby incorporatedherein by reference.

BACKGROUND OF THE INVENTION

The invention lies in the field of mechanics and electrical engineeringand can be used particularly advantageously in the field ofmicromechanics. Inter alia, applications in medical engineering areparticularly advantageous.

BRIEF SUMMARY OF THE INVENTION

When introducing assemblies into channel systems or at locations whichare particularly difficult to access, problems often occur, similarly towhen implanting assemblies into a patient body, due to the fact thatassemblies of this type must be brought to their target positionsthrough through-openings or channels that are as narrow as possible, butonce arrived at the target position are to provide the greatest possibleeffect, inter alia by maximal dimensions.

In medical engineering, it is known for this purpose to adopt anapproach in which corresponding assemblies are compressed before beingintroduced into the patient body and to the target location, areinserted in the compressed state, and are then expanded. This haspreviously already been applied in the case of expandable heart-assistcatheter pumps and also in the case of implantable stents. In thenon-medical field, inspection cradles by way of example can be sentthrough tubes and can likewise be expanded once they have reached largercavities or can be used to deploy suitable tools or sensors.

In the medical field drivable, expandable assemblies were until nowdriven, when implanted, by motors outside the body by means of flexibleshafts. In the case of heart-assist blood pumps, a pump rotor forexample is connected to a motor outside the body by a port by means of aflexible shaft, which extends through a hollow catheter within bloodvessels. Very high demands are sometimes placed on transfer systems ofthis type, for example in the form of flexible shafts, since these highrotational speeds must be transferred over a relatively long period oftime without significant wear and usually under lubrication conditionswhich are not optimal. It would therefore be advantageous to be able todispense with transfer systems of this type.

Against the background of the prior art, the object of the presentinvention is therefore to design a motor in such a way that it can alsobe transported through narrow channels.

The object is achieved by the features described herein.

The motor according to the invention has a stator and a rotor that canbe driven about an axial direction, wherein, in order to achieve theobject, of these, at least one, in particular the stator, which has awinding arrangement that can be supplied with a current, is radiallycompressible and expandable.

The term radial compressibility within the scope of the presentinvention is to be understood to mean that the diameter of the elementin question can be reduced at least in part in relation to the axis ofrotation of the motor. This may include all possibilities of a uniformdiameter reduction, in which case merely the diameter of a cylindricalbody changes, without otherwise changing in terms of shape. However, theradial compressibility may also be understood to mean diameterreductions of the stator and/or the rotor in just one axis, which forexample is generated by pressing the element flat or, if the element(stator and/or rotor) is composed of different circular discs, bytilting the circular discs relative to the axis of rotation. In thespecified case the diameter is reduced in a first directionperpendicular to the axis of rotation, whereas it remains constant inthe direction perpendicular to the first direction.

Compressible stators of this type having a winding arrangement that canbe supplied with a current are not known from the prior art. Inaccordance with the invention, the winding arrangement itself inparticular may be radially compressible. A winding arrangement of thistype can be compressed before being introduced into a channel, wherebythe overall diameter of the motor is reduced particularly when thestator determines the outer diameter of the motor. By way of example,the stator may surround the rotor coaxially in the operating state. Inthis case, a radial compression of the stator is equivalent to a radialcompression of the motor. The stator may also be surrounded by ahousing, which for example may be resilient and then compressible andexpandable with the stator. By way of example, the housing may consistsubstantially of a resilient film, which is stretched over the stator.However, it may also be that the motor does not have a housing.

When the stator surrounds the rotor coaxially, the possibilities forcompression of the stator are subject to narrow limits by the internallyarranged rotor. A further compression of the stator is advantageouslypossible for example when the rotor and stator can be displaced relativeto one another in the axial direction between a first position, in whichthe stator is radially compressible, and a second position, in which thestator is radially expanded. In this case, for compression of thestator, the rotor can be firstly slid out therefrom axially, and thestator can then be compressed, for example up to the outer diameter ofthe rotor. The stator and rotor can then be slid axially one after theother through a channel to the target position. If the rotor per se isnot compressible, a further compression of the stator under the externaldimension of the rotor therefore is not provided or is not possible insome exemplary embodiments.

If the stator and rotor have arrived at the target position, the statorcan be expanded again or can expand automatically, and the rotor can bedrawn into the stator in the axial direction.

The stator may also be radially expanded in that the rotor is displacedor drawn into the stator and this is radially expanded during thedisplacement movement. For this purpose, the rotor may be formed in aconically tapering manner at least in portions.

In accordance with a further advantageous variant of the invention, therotor is compressible in the radial direction. If the rotor is alsocompressible in the radial direction, the rotor in a variant may remainin the stator, and both can be radially compressed jointly, otherwise itis also conceivable to displace the rotor out from the stator and tocompress these both radially independently of one another.

By way of example, the rotor for this purpose may have a plurality ofmagnets, which can be referred to as magnet elements and which arereversibly movable relative to one another in particular in the axialdirection. The rotor by way of example may have permanent magnets orelectromagnets having a ferromagnetic core, which are each to bedesignated as magnet elements. Such magnets can each be divided intomagnet segments in such a way that individual segments of a magnet canbe displaced relative to one another in order to reduce the diameter ofthe rotor by reduction of the dimensions of the magnets in the radialdirection.

By way of example, at least one magnet may consist of wedge-shapedsegments, which can be pushed together and away from one another in theaxial direction and when pushed away from one another take up less spaceon the whole, as considered in the radial direction, than when in thestate pushed together. However, a division in different other planes mayalso be provided, wherein it is also conceivable to displace theindividual segments of the magnet in the circumferential direction ofthe rotor and/or in the radial direction of the motor. The segments ofthe magnet may also be referred to as magnet elements, and therefore theterm magnet elements includes both the segments of the magnet and entiremagnets.

It is important that the described movements of the magnets or thesegments of magnets lead to a diameter reduction, are reversible, andcan be reversed in a simple manner for a subsequent expansion of therotor.

In order to enable the simplest possible radial compression of a stator,the winding arrangement advantageously may have at least one sub-windingfor example, which is reversibly deformable. By way of example,sub-windings of this type may be resilient and for example may containresilient leads, which allow a temporarily deformation of a sub-winding.A deformation of this type may be both resilient and plastic.

It may also be that the winding arrangement has at least twosub-windings, which can be displaced reversibly relative to one another.Sub-windings of this type for example may be non-cast or may be cast ina rigid or resilient casting material and may be slid one over the otherin a shingle-like manner, in particular in the circumferential directionof the stator, in the event of radial compression of the stator.However, a pivoting or rotation of sub-windings is also conceivable,provided the rotor has been removed from the stator.

For improved deformability of the winding arrangement, the windingarrangement for example may have at least one sub-winding cast in aresilient material. By way of example, a sub-winding may be cast in anelastomer, for example in a silicone elastomer or in a rubber material.Larger parts of the winding arrangement, for example even the entirewinding arrangement, may also be cast in a resilient material of thistype.

In order to increase the efficacy, the resilient matrix may be providedin particular on the outer side with a ferromagnetic filler.

If individual parts of the winding arrangement are each cast separately,the resilient deformability can thus also be combined with adisplaceability, for example when the sub-windings have resilient leadsand/or are cast in a resilient material.

By way of example, the winding arrangement may also have, at least inpart, leads consisting of a memory alloy. In this case, a sub-winding orthe entire winding arrangement may assume a desired shape and size atthe target location, for example by selective setting of a targettemperature. In the case of medical applications, the alloy for examplemay be set such that the winding arrangement assumes the desired targetshape once the body temperature of a patient has been assumed.

In order to ensure a repeated compression and expansion and areproducible course of the compression and expansion movement in thecase of a winding arrangement consisting of a plurality of sub-windingsmovable relative to one another, it may also be advantageous for examplefor the winding arrangement to have bend and/or kink regions definedbetween elements movable relative to one another. Bend and/or kinkregions of this type may be provided in the form of soft and/or flexiblelead parts, for example by providing length portions of the leads formedas stranded wires or by particularly thin lead regions.

In the case of a motor of the above-described type, in order to be ableto displace the rotor and stator relative to one another in the targetposition, even from a distance, the invention advantageously provides aconnection element, which extends away from the motor and by means ofwhich the rotor and stator can be displaced relative to one another inthe axial direction. The connection element can be formed as a typicalmanipulation element, for example in the manner of a Bowden cable or thelike, wherein different parts of the connection element can be connectedto the stator on the one hand and the rotor on the other hand.

By means of the connection element, a relative displacement of thestator and rotor and therefore in the target position a drawing of therotor into the stator is possible, wherein the stator either has beenalready expanded beforehand or is radially expanded by drawing the rotorinto the stator.

The invention also relates to an implantation arrangement having ahollow catheter and a stator and a rotor arranged compressed therein.Within the scope of an implantation arrangement of this type, theradially compressible motor can be drawn in simple form into a hollowcatheter, wherein the motor is usually received in the hollow catheterin the compressed form. The hollow catheter may then for example beintroduced by means of a port into a blood vessel of a patient,displaced through this, and taken to a target position, for exampleintroduced into an aortic arch, into a cardiac valve or into aventricle. The hollow catheter may then be retracted, wherein the motoris slid out therefrom and is either radially expanded during thisprocess or thereafter.

The invention also relates to a motor of the above-described type and toan implantation arrangement, and to a method for positioning a motor ofthe described type, wherein the stator and the rotor are displacedthrough a channel to a target position, wherein at least the stator isradially compressed, and at least the stator is radially expandedthereafter.

In accordance with an advantageous embodiment of the method the statorand the rotor are displaced relative to one another in the axialdirection once the stator and rotor have been displaced into the targetposition.

The invention also relates to a pump, in particular blood pump,containing a motor having a stator and a rotor that can be driven aboutthe axial direction, wherein, of these, at least one, in particular thestator, which has a winding arrangement that can be supplied with acurrent, is radially compressible and expandable. Here, the motor andthe pump are advantageously integrated heavily in one another. It isthus possible to produce pumps of particularly small structure; inparticular it is advantageous for pumps having a very small radialdiameter to be brought to a site of use and then radially expanded therein order to provide the actual pump performance.

Here, in accordance with an embodiment, the rotor is connected to a pumprotor, wherein the pump rotor has a blading for conveying fluids. By wayof example, the pump rotor can be mounted on the actual magnetic rotoror may surround this radially; it is also possible however for these tobe interconnected in another way, for example in that the magnetic rotoris cast/embedded in the pump rotor.

In accordance with a further embodiment the pump rotor in the operatingstate is located at least partially within the stator. A radial layeredarrangement is thus provided in the operating state and, startingradially outwardly towards the center, is as follows: 1. stator, 2. pumprotor, 3. magnetic rotor. In other forms in which the pump rotor and themagnetic motor are interconnected, this potentially may also bedifferent.

In accordance with an advantageous embodiment, the pump rotor isradially compressible, in particular the pump rotor is radiallyresiliently compressible. Here, in accordance with a variant, theblading of the pump rotor is primarily resiliently compressible and forexample bears against the hub of the pump rotor.

Different variants of the pump according to the invention are possible,wherein all variants of the motors according to the present inventioncan be used for the pump.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be shown in various figures and described hereinafteron the basis of exemplary embodiments. In the figures

FIG. 1 shows a schematic illustration of a motor having a rotor and astator in a longitudinal section,

FIG. 2 shows the motor from FIG. 1 in a compressed form, wherein thestator and rotor are pulled axially away from one another,

FIG. 3 schematically shows, in a modified form, individual wires of thewinding arrangement with a length reserve in the form of a spiraled ormeandering course,

FIG. 4 a shows an illustration of a winding arrangement in an axialview, compressed in the left-hand part of the figure in the spiraledform of the lead, and expanded on the right-hand side,

FIG. 4 b shows a winding arrangement as considered in the axialdirection, compressed in the left-hand part of the figure in themeandering form of the lead, and radially expanded in the right-handpart,

FIG. 5 shows, in a three-dimensional view, a winding arrangement havinga plurality of sub-windings, which in the unrolled state havesubstantially a rhombic or trapezoidal design,

FIG. 6 schematically shows, in a three-dimensional view, the course ofan individual winding of a sub-winding from FIG. 5 ,

FIG. 7 schematically shows, in a view in the axial direction, thearrangement of different sub-windings relative to one another at thecircumference of the winding arrangement in the radially expanded state,

FIG. 8 shows the arrangement of sub-windings from FIG. 7 in the radiallycompressed state,

FIG. 9 schematically shows a longitudinal section through a motor havinga stator and a rotor, wherein the rotor is encapsulated, in theassembled, expanded state,

FIG. 10 shows the motor from FIG. 9 in the compressed state pulled apartaxially,

FIG. 11 shows a stator and a rotor arranged axially in succession,wherein the stator is radially compressed and both have a manipulationmeans,

FIG. 12 shows a cross section through a stator, of which the windingarrangement is divided in the circumferential direction into foursub-windings,

FIG. 13 shows a compressed state of the stator from FIG. 12 , in whichthe sub-windings have been changed mechanically radially inwardly byradial pressure,

FIG. 14 shows an illustration of the stator from FIGS. 12 and 13 in thefurther compressed state,

FIG. 15 schematically shows, in the axial direction, the illustration ofa rotor having two magnets,

FIG. 16 shows a side view of a magnet of a rotor divided into segmentsand radially compressible,

FIG. 17 shows an illustration of a stator having a winding arrangementdivisible in the axial direction,

FIG. 18 shows an illustration of a stator having a rotor arrangedtherein and a compressible pump rotor arranged on the rotor in theexpanded state,

FIG. 19 shows an illustration of the device from FIG. 18 in thecompressed state, and

FIG. 20 shows an illustration of a stator having a pump rotor removedtherefrom axially, in a side view.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates, in a longitudinal section, a stator 2and a rotor 1 of an electric motor. Further parts and details have beenomitted for the sake of clarity. The stator has a schematicallyindicated cylindrical winding arrangement, which may consist of one ormore sub-windings. The rotor 1 has at least one permanent magnet and ahub, which is connected to a shaft 3. The magnetic poles of the rotor 1or of the magnet/magnets thereof can be driven in the magnetic field ofthe stator 2. The shaft 3 is usually rotatably mounted at one or morepoints in plain or ball bearings. The bearings may be fixedly connectedfor example to the stator 2 or to a housing (not illustrated) of thestator or the motor as a whole. In FIG. 1 it can be seen that thestator, which surrounds the rotor 1 concentrically and coaxially, has adiameter D in the radially expanded state illustrated there.

FIG. 2 shows the elements of a motor already illustrated in FIG. 1 ,specifically a rotor 1 and a winding arrangement of a stator 2, whereinthe rotor and stator are pulled apart from one another in the axialdirection 4. The stator and the rotor do not overlap one another in theaxial direction in this state. The stator is radially compressed byradial compression of the winding arrangement on the whole to thediameter d, which is equal to or smaller than the outer diameter of therotor 1.

Is thus clear that, due to the divisibility of the motor and thedisplaceability of the stator relative to the rotor, the stator isradially compressible as soon as the rotor has been removed therefrom.

Irrespective of this and in addition, the rotor may also be compressiblein the radial direction. In this case, the stator and rotor may also beradially compressed jointly in the assembled state, or can be displacedaxially relative to one another and can both be radially compressedseparately from one another. In the latter case it is useful, but notnecessary, for both elements, i.e., both the stator and the rotor, to becompressible approximately to the same outer diameter.

FIG. 3 in the upper region shows a first lead 5 of a winding arrangementof a motor according to the invention in the compressed state, whereinthe lead extends in a spiraled manner. If a winding arrangement orsub-winding is formed from this lead extending in a spiraled manner,this winding arrangement or sub-winding can radially expand if thewinding wire 5 is extended and later can be radially compressed again.In the lower region of FIG. 3 a lead 6 is illustrated, which in thecompressed state has a meandering form which can be extended whentransitioning into an expanded state.

In FIG. 4 a a lead 5 that is spiraled in the compressed state isillustrated schematically in the left-hand part and likewise in thecompressed state is illustrated schematically in the form of a circularring, which symbolizes a winding arrangement. In the right-hand part ofFIG. 4 a , an expanded form of the stator is illustrated in axial view,in which the winding lead(s) is/are elongated and accordingly thewinding arrangement and/or the sub-windings is/are likewise expanded.The stator in the right-hand part of FIG. 4 a has the enlarged diameterD, whereas in the compressed state illustrated in the left-hand part ofFIG. 4 a it has the reduced diameter d.

In FIG. 4 b a compressed lead 6 is illustrated in meandering form,which, as considered in the axial direction, is arranged in a circularring form, which represents a winding arrangement of a stator. Thearrangement has the compressed outer diameter d. In the right-hand partof FIG. 4 b the same stator is illustrated in the radially expandedstate, wherein the winding lead(s) is/are elongated, or at least arefurther extended than in the compressed state.

The transition between the compressed and expanded state of the statorcan be implemented for example by an application of force, in that thestator is brought by means of radial external pressure into a compressedform and, when the external radial compression force is cancelled,expands resiliently again of its own accord.

Conversely, the stator may also have a reduced diameter without externalforce application, and may be expandable by force application.

As a further alternative, it may be that the winding arrangement hasleads made of what are known as memory alloys, which for example in theevent of temperature changes change their shape and in definedtemperature ranges each have reproducible shapes. Such memory alloys maybe, for example, NiTi (nickel-titanium; nitinol), NiTiCu(nickel-titanium-copper), CuZn (copper-zinc), CuZnAl(copper-zinc-aluminium), CuAlNi (copper-aluminium-nickel), FeNiAl(iron-nickel-aluminium), or FeMnSi (iron-manganese-silicon). Alloys ofthis type are also referred to as hyperelastic alloys.

In addition to the described properties of the winding arrangement, acasting of the entire winding arrangement or individual sub-windings ina resilient material, such as a silicone elastomer or a rubber, may alsobe provided, which is resiliently deformable per se. There may also beno casting of the winding arrangement, or a casting in a non-resilientmaterial, wherein the casting of individual sub-windings is performedseparately and the sub-windings together with the respective castingmaterial are movable relative to one another. Such configurations willbe discussed in greater detail further below.

FIG. 5 , in a perspective view, shows a substantially hollow-cylindricalwinding arrangement, which consists of a plurality of sub-windings. Eachsub-winding consists of a plurality of windings of a lead and has twoelectrical terminals for voltage supply and current feed. The windingarrangement as a whole may also have terminal leads or electricalterminals.

Each sub-winding of the illustrated winding arrangement in the unrolledstate has a rhombic basic shape. The individual sub-windings overlap oneanother in the circumferential direction of the winding arrangement. Theindividual sub-windings 7, 8 of the winding arrangement from FIG. 5 haveelectrical terminals 9, 10 for supplying a current to the stator windingarrangement.

In FIG. 6 an individual sub-winding 7 is illustrated, symbolized by anindividual winding of a winding lead, and is designated by referencesign 11. The sub-winding 11 has two electrical connections 12, 13 forsupplying a current. In FIG. 6 a hollow cylinder is illustratedschematically, over the circumference of which the part-cylindricalsub-windings are distributed in a manner overlapping one another andoffset relative to one another in the circumferential direction.

In FIG. 7 a plurality of sub-windings 7, 8 of a winding arrangement areshown schematically in a view in the axial direction. The individualsub-windings 7, 8 each have a radially external part 7 a and a radiallyinner part 7 b, wherein each radially inner part is overlaid by thefollowing sub-winding 8, more specifically by the radially external partthereof. In this way, a roof-tile-like nesting of the sub-windings isprovided along the circumferential line of the stator.

If the sub-windings are movable relative to one another, these can beslid further over one another in a shingle-like manner, and thereforethe diameter of the overall arrangement and the circumference of thewinding arrangement can be reduced. An example of a compressed state ofsuch a compression movement is shown in FIG. 8 , in which in each casetwo windings 7, 8 are slid one over the other, such that they overlapone another completely in the circumferential direction of the windingarrangement. This slidability of the individual sub-windings over oneanother is conceivable with non-cast sub-windings and also with castsub-windings. If the individual sub-windings are cast, it isadvantageous if the casting material enables easy sliding relative toone another of two bodies consisting thereof.

FIG. 9 , in a longitudinal section, shows a motor having a radiallyexpanded stator 2 and a rotor 1, which has an encapsulation 14 in theform of a hollow cylinder, which surrounds the magnet body of the rotorand which for example also carries the bearings 15, 16. The shaft 3 ofthe rotor is mounted with little friction in the bearings 15, 16, whichmay be formed as plain or ball bearings. The diameter of the overallstructure of the motor according to FIG. 9 in the expanded, assembledstate ready for operation is specified by D.

By contrast, the same motor having the same elements, i.e., a rotorencapsulated within an encapsulation 14 and a stator 2 having a windingarrangement, is illustrated in FIG. 10 in the compressed state, whereinthe stator 2 has been displaced to such an extent in the axial directionrelative to the rotor 1 that the rotor is located outside the stator.The stator 2 is then radially compressible independently of the rotor 1up to the outer diameter of the rotor.

FIG. 11 shows a design of a motor having a rotor 1′ and a stator 2′,wherein these are illustrated in the compressed position pulled apartaxially from one another. The rotor 1′ has an encapsulation, in whichthe magnet arrangement of the rotor, supported by two bearings, canrotate. The encapsulation of the rotor has a conical tapered portion 17and a connection to a strand-shaped manipulation element 18, which isfastened to the encapsulation or to a bearing and enables an axialrelative movement of the rotor relative to the stator 2′. At the sametime, the stator 2′ is connected to a second manipulation element 19,for example in the form of a tube or hose, through which for example themanipulation element 18 can be guided. The manipulation elements 18, 19,which jointly form a connection element to the motor, can be jointlyactuated from a remote location in order to perform a relative movementof the stator and rotor relative to one another and for example toradially expand these by means of the insertion of the encapsulation ofthe rotor 1′ into the winding arrangement of the stator 2′.

FIG. 12 shows a particular winding arrangement consisting of fourseparate sub-windings 20, 21, 22, 23 each cast separately in a resilientmaterial. Each of these sub-windings is formed as part of a hollowcylinder, and the sub-windings can be assembled with their cast bodiesto form an overall hollow cylinder.

If a force is exerted onto the winding arrangement radially from theoutside, the constellation as illustrated in FIG. 13 is provided,wherein the individual cast bodies and sub-windings turn radiallyinwardly. The individual cast bodies of the sub-windings may beconnected movably to one another for example by living hinges. In thestate illustrated in FIG. 13 , the winding arrangement in the radialdirection already occupies a much smaller space than in the formillustrated in FIG. 12 . With a further radial compression, theindividual sub-windings are further compressed radially inwardly, whichis additionally made possible by a deformability of the cast body. Withfull compression, the form illustrated in FIG. 14 is provided. This canbe automatically expandable back into the form illustrated in FIG. 12with cancellation of the radially inwardly acting compression forces,wherein the restoring forces can be applied for example by theresiliently deformed cast bodies, but also by the winding leadsthemselves, or by both, jointly. If the individual sub-windings are notcast, a corresponding deformation of the winding leads can also takeplace reversibly within each sub-winding. FIG. 15 , in an illustrationin the axial direction, shows two magnets 24, 25 arranged at rightangles on one another, which can be driven in the magnetic field of thewinding arrangement. The magnets 24, 25 are fixedly connected to theshaft 3 of the rotor.

FIG. 16 illustrates the division of a magnet 24 along the surface 26,whereby two segments 24 a, 24 b of the magnet 24 are produced, whicheach form a magnet element. The magnet 24 in the state illustrated bysolid lines, has the form of a cuboid. The constellation in which thesegment 24 is displaced in the axial direction 4 along the surface 26relative to the segment 24 b is shown in a dashed manner. An extensionof the magnet 24 is provided in the axial direction, and a compressionfrom the diameter D to the diameter d, as specified in FIG. 16 in theright-hand part, is provided in a radial direction. As a result of theshown construction of the rotor, this can also be radially compressible,such that the motor is compressible either in the assembled state byjoint compression of stator and rotor or is also compressible merely byradial compression of the stator in the state pulled apart axially.

The motor can therefore be compressed in order to be brought to its siteof use; for example, it may be implantable as a drive apparatus for ablood pump and may be displaced through a blood vessel in the compressedstate within a patient body to a site of use. There, the motor can beexpanded, as can a blood pump for example, and the motor in the expandedstate can build up the necessary torques or the required power to drivea pump.

FIG. 17 shows a design variant in which the winding arrangement isdivided into a plurality of sub-windings 27, 28, which are eachconstructed in the form of a circular ring and, arranged axially insuccession, form a hollow-cylindrical winding arrangement. If, in suchan arrangement, the circular-annular sub-windings are tilted, the crosssection of the winding means is thus elliptical, but is compressed indiameter in an axis 29 relative to the untilted arrangement. In the axis30 arranged at right angles hereto, the diameter remains the same.Nevertheless, a form more favorable for the positioning of the motor maybe provided with the tilted arrangement. The tilting can be reversed atany moment following the positioning of the motor.

FIG. 18 shows a device consisting of a stator according to FIG. 7 havingthe windings 7, 8 already described there. A magnetic rotor 1″, to whicha radially compressible pump rotor 29 is connected in such a way that itcan rotate jointly with the rotor 1″ about the same axis, is located inthis stator. In the exemplary embodiment the pump rotor is formed from aresilient, preferably hyperelastic plastics material, which makes itpossible for the pump rotor 29 to collapse in the event of compressionof the stator and to resiliently or hyperelastically expand back againinto the starting form in the event of expansion of the stator.

FIG. 19 schematically illustrates how the stator compresses similarly toFIG. 8 , wherein the pump rotor 29 likewise assumes a compressed form.Here, the blades of the pump rotor fold around the axis of the rotor andbear against the hub of the pump rotor.

In principle, the device may also be formed such that the rotor 1″together with the pump rotor 29 can be axially removed from the rotor ina manner corresponding to FIG. 20 . The pump rotor 29 and the stator arethus arranged axially in succession. In this state the stator and thepump rotor can be jointly compressed, which enables a further reductionof the compressed diameter compared with the embodiment in FIG. 19 .

The pump rotor can be formed in principle in very different ways.Besides the variant formed from resilient or hyperelastic plasticsmaterial shown in FIGS. 18 and 19 , various other variants are knownfrom the prior art, for example from U.S. Pat. Nos. 4,753,221;5,749,855; 7,393,181; US 2009/0062597 A1; EP 2047873 A1; US 2011/0275884A1; EP 2229965 A1; WO 2010 149393 A1; EP 2299119 A1; EP 2338540 A1; EP2338541 A1; EP 2363157; EP 2407185 A1; EP 2407187 A1; EP 2407186 A1.

The invention claimed is:
 1. A motor, comprising: a rotor that can bedriven about an axial direction; and a stator, which has a windingarrangement that can be supplied with a current; wherein the stator isradially compressible and expandable; and wherein the windingarrangement has at least one sub-winding cast in a resilient material.2. The motor according to claim 1, wherein the rotor and the stator canbe displaced relative to one another in the axial direction between afirst position, in which the stator is radially compressible, and asecond position, in which the stator is radially expanded.
 3. The motoraccording to claim 2, further comprising a connection element, whichextends away from the motor and by means of which the rotor and statorare displaceable relative to one another in the axial direction.
 4. Themotor according to claim 1, wherein the rotor is compressible in theradial direction.
 5. The motor according to claim 4, wherein the rotorhas a plurality of magnet elements, which are reversibly movablerelative to one another.
 6. The motor according to claim 1, wherein thewinding arrangement has at least two sub-windings which are cast inseparate sub-bodies and are movable relative to one another.
 7. Themotor according to claim 1, wherein the winding arrangement has leadsconsisting at least partially of a memory alloy.
 8. The motor accordingto claim 1, wherein the winding arrangement has elements movablerelative to one another and bend and/or kink regions defined betweensaid elements.
 9. The motor according to claim 1, wherein the rotor isradially compressible and expandable.
 10. The motor according to claim1, wherein the at least one sub-winding is a plurality of side-windingsthat form a cylinder.
 11. The motor according to claim 10, wherein theplurality of side-windings are connected by living hinges.
 12. A methodfor positioning a motor, the method comprising: inserting a stator and arotor through a channel to a target position, wherein at least thestator is radially compressed, wherein the stator has a windingarrangement that can be supplied with a current and that has at leastone sub-winding cast in a resilient material; and radially expanding atleast the stator such that the at least one sub-winding cast in aresilient material also expands, thereafter.
 13. The method according toclaim 12, further comprising: after inserting the stator and the rotorthrough a channel into the target position, displacing the stator andthe rotor relative to one another in an axial direction.
 14. The methodaccording to claim 12, wherein the at least one sub-winding is aplurality of side-windings that form a cylinder.
 15. The methodaccording to claim 14, wherein the plurality of side-windings areconnected by living hinges.
 16. A pump comprising: a motor having astator and a rotor, wherein the rotor can be driven about an axialdirection, wherein the stator, which has a winding arrangement that canbe supplied with a current, is radially compressible and expandable andwherein the winding arrangement has at least one sub-winding cast in aresilient material.
 17. The pump according to claim 16, wherein therotor is connected to a pump rotor, wherein the pump rotor has a bladefor conveying fluids.
 18. The pump according to claim 17, wherein thepump rotor in an operating state is located at least partially withinthe stator.
 19. The pump according to claim 17, wherein the pump rotoris radially compressible.
 20. The pump according to claim 17, whereinthe pump rotor is radially resiliently compressible.
 21. The pumpaccording to claim 16, wherein the rotor is radially compressible andexpandable.
 22. The pump of claim 16, wherein the at least onesub-winding is a plurality of side-windings that form a cylinder. 23.The pump of claim 22, wherein the plurality of side-windings areconnected by living hinges.